MOREHEAD CITY, N.C. (AP) — Hurricane Irene opened its assault on the Eastern Seaboard on Saturday by lashing the North Carolina coast with wind as strong as 115 mph and pounding shoreline homes with waves. Farther north, authorities readied a massive shutdown of trains and airports, with 2 million people ordered out of the way.

At least three people died because of the storm.

The center of the storm, which was estimated to be some 500 miles wide, passed over North Carolina’s Outer Banks for its official landfall just after 7:30 a.m. EDT. The hurricane’s vast reach traced the East Coast from Myrtle Beach, S.C., to just below Cape Cod. Tropical storm conditions battered Virginia, Maryland and Delaware, with the worst to come.

On Saturday afternoon, forecasters said Irene’s effects could be felt as far north as Canada even after it weakens. A tropical storm warning extended from the U.S. border to Nova Scotia’s southern coast.

Irene weakened slightly, with sustained winds down to 85 mph from about 100 a day earlier, making it a Category 1, the least threatening on the scale. The National Hurricane Center reported gusts of 115 mph and waves as high as 7 feet.

At least three deaths were directly caused by the storm. In Nash County, N.C., emergency officials said a man was crushed by a large limb that blew off a tree. In Newport News, Va., a city spokeswoman said an 11-year-old boy was killed when Irene’s winds sent a tree crashing through his apartment building. Winds had been gusting well above 60 mph in the area. Also in Virginia, someone was killed when a tree fell onto a car.

Hurricane-force winds arrived near Jacksonville, N.C., at first light, and wind-whipped rain lashed the resort town of Nags Head.

Tall waves covered the beach, and the surf pushed as high as the backs of some of the houses and hotels fronting the strand.

“There’s nothing you can do now but wait. You can hear the wind and it’s scary,” said Leon Reasor, who rode out the storm in the Outer Banks town of Buxton. “Things are banging against the house. I hope it doesn’t get worse, but I know it will. I just hate hurricanes.”

At least two piers on the Outer Banks were wiped out, the roof of a car dealership was ripped away, and a hospital in Morehead City was running on generators. In Jones County, part of the roof was torn from the county civic center, where some 70 people were seeking shelter.

In all, more than 800,000 people were without power on the East Coast.

The Red Cross had opened 63 shelters in North Carolina by Saturday afternoon, with more than 5,573 people registering to stay. At the shelter on the Elizabeth City State University campus, children shrieked and played while their parents watched the storm unfold. Latoya Bryant watched her 2- and 4-year-olds play, saying she told them they could go home once the storm was over.

“They want to play in the rain, though,” Bryant said. “You can’t play in this rain.”

In the Northeast, unaccustomed to tropical weather of any strength, authorities made plans to bring the basic structures of travel grinding to a halt. The New York City subway, the largest in the United States, was making its last runs at noon, and all five area airports were accepting only a few final hours’ worth of flights.

The New York transit system carries 5 million people on weekdays, fewer on weekends, and has never been shut for weather.

Transit systems in New Jersey, Baltimore and Philadelphia also announced plans to shut down. Washington declared a state of emergency. Days earlier, buildings had been evacuated after an earthquake rattled the D.C. area.

New York City ordered 300,000 people to leave low-lying areas, including the Battery Park City neighborhood at the southern tip of Manhattan, the beachfront Rockaways in Queens and Coney Island in Brooklyn. But it was not clear how many people would get out, or how they would do it.

“How can I get out of Coney Island?” said Abe Feinstein, 82, who has lived for half a century on the eighth floor of a building overlooking the boardwalk. “What am I going to do? Run with this walker?”

Authorities in New York said they would not arrest people who chose to stay, but Mayor Michael Bloomberg warned on Friday: “If you don’t follow this, people may die.”

Streets and subway cars were much emptier than on a typical Saturday morning. On Wall Street, sandbags were placed around subway grates nearest the East River, which is expected to surge as the worst hits New York.

The city’s largest power company said it could cut power to some neighborhoods if the storm causes serious flooding. Salt water can damage power lines, and cutting power would speed repairs.

In all, evacuation orders covered about 2.3 million people, including 1 million in New Jersey, 315,000 in Maryland, 300,000 in North Carolina, 200,000 in Virginia and 100,000 in Delaware.

Authorities and experts said it was probably the most people ever threatened by a single storm in the United States.

Airlines said 8,300 flights were canceled, including 3,000 on Saturday. Greyhound suspended bus service between Richmond, Va., and Boston. Amtrak canceled trains in the Northeast for Sunday.

Forecasters said the core of Irene would roll up the mid-Atlantic coast Saturday night and over southern New England on Sunday. Late Saturday morning, Irene was centered about 95 miles south of Norfolk, Va. It was moving north-northeast at 15 mph.

Maximum sustained winds remained around 85 mph.

North of the Outer Banks, the storm pounded the Hampton Roads region of southeast Virginia, a jagged network of inlets and rivers that floods easily. Emergency officials there were less worried about the wind and more about storm surge, the high waves that accompany a hurricane. Gas stations there were low on fuel, and grocery stores scrambled to keep water and bread on the shelves.

In Delaware, Gov. Jack Markell ordered an evacuation of coastal areas on the peninsula that the state shares with Maryland and Virginia. In Atlantic City, N.J., all 11 casinos announced they would shut down for only the third time since gambling became legal there 33 years ago.

In Baltimore’s Fells Point, one of the city’s oldest waterfront neighborhoods, people filled sandbags and placed them at building entrances. A few miles away at the Port of Baltimore, vehicles and cranes continued to unload huge cargo ships that were rushing to offload and get away from the storm.

A steady rain fell on the boardwalk at Ocean City, Md., where a small amusement park was shut down and darkened — including a ride called the Hurricane. Businesses were boarded up, many painted with messages like “Irene don’t be mean!”

Charlie Koetzle, 55, who has lived in Ocean City for a decade, came to the boardwalk in swim trunks and flip-flops to look at the sea. While his neighbors and most everyone else had evacuated, Koetzle said he told authorities he wasn’t leaving.

To ride out the storm, he had stocked up with soda, roast beef, peanut butter, tuna, nine packs of cigarettes and a detective novel.